1. What is a Velocity Stack Length Calculator?

Definition: This calculator determines the optimal length of a velocity stack based on the speed of sound, resonant frequency, and a tuning factor.

Purpose: It helps automotive engineers and enthusiasts design intake systems for optimal engine performance.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( L \) — Stack length (meters)
• \( c \) — Speed of sound (m/s)
• \( f \) — Resonant frequency (Hz)
• \( k \) — Tuning factor (dimensionless)

Explanation: The speed of sound is divided by the resonant frequency to determine the wavelength, then multiplied by a tuning factor to get the optimal stack length.

3. Importance of Velocity Stack Length

Details: Proper stack length tuning improves volumetric efficiency, optimizes power band, and enhances throttle response.

4. Using the Calculator

Tips: Enter the speed of sound (default 343 m/s at 20°C), desired resonant frequency, and tuning factor (default 0.25 for quarter-wave tuning). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is the speed of sound important?
A: The speed of sound affects wave propagation in the intake system, which varies with temperature (about 343 m/s at 20°C).

Q2: How do I determine resonant frequency?
A: This is typically the engine RPM where you want peak torque, converted to Hz (RPM/60).

Q3: What tuning factors are commonly used?
A: 0.25 for quarter-wave tuning, 0.5 for half-wave, and 0.75 for three-quarter-wave tuning.

Q4: Should I adjust for temperature?
A: Yes, the speed of sound changes with temperature (about +0.6 m/s per °C increase).

Q5: Does this work for all engine types?
A: The principle applies to most piston engines, but optimal length may vary based on specific intake designs.